A magnetometer is an electronic device for detecting the magnitude and/or orientation of a magnetic field. It is customary to test magnetometers in magnetic fields of known strength and orientation to determine their response and, in some cases adjust or “trim” the magnetometers to provide a predetermined output in response to known magnetic fields. This process is generally referred to as calibration and is a routine aspect of producing useful magnetometers. In some cases, other tests relating to, for example, acceleration, temperature, etc., may also be performed on magnetometers, especially where the magnetometers are intended for use in stressful environments.